Method for double-side vacuum film formation and laminate obtainable by the method

ABSTRACT

The film formation method comprises the steps of: unrolling and feeding an elongated substrate wound in a roll form from a first roll chamber in a direction from the first roll chamber toward a second roll chamber, using a first surface as a surface for film formation; degassing the fed substrate; forming a first material film on the first surface of the degassed substrate in a first film formation chamber; forming a second material film on the first material film in a second film formation chamber; taking up the substrate in a roll form in the second roll chamber, the substrate having the material films formed thereon; unrolling and feeding the taken up substrate from the first roll chamber in the direction, using a second surface opposite the first surface of the substrate as a surface for film formation; and repeating all the above treatments.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the priority of Japanese Patent Application No.2011-166669 filed on Jul. 29, 2011, and Japanese Patent Application No.2012-156280 filed on Jul. 12, 2012 in the JPO (Japan Patent Office), thedisclosure of which is incorporated herein in their entirety byreference.

TECHNICAL FIELD

The present invention relates to a method for film formation, and inparticular to a method for double-side vacuum film formation capable ofsubjecting an elongated substrate to vacuum film formation, and alaminate obtainable by the method.

BACKGROUND ART

Various film formation processes, such as a vacuum vapor depositionprocess, a sputtering process and an ion plating process, have beendeveloped. A laminate obtained by such a film formation process iswidely utilized in production of display devices, such as liquid crystaldisplays or organic LE (Light Emitting) displays, semiconductor devices,etc. In the display devices, the semiconductor devices, etc., thelaminate is usable as a protective film, and various types of functionalfilms, such as an optical filter and an anti-reflection film.

Late years, demand for device units using the functional films, such asa LCD (Liquid Crystal Display) TV, a mobile phone and a video gamemachine, has been rapidly expanded. Along with expansion of the demand,it has become an urgent matter to develop a technique for mass-producinga functional film within a short period of time. In order to respond tothis need, a roll-to-roll technique has been developed. The roll-to-rolltechnique is designed to unroll and feed an elongated substrate wound ina roll form, between two rolls, so as to enable continuous filmformation, thereby increasing efficiency of a film formation operation.

One example of a film formation method using a roll-to-roll technique isdisclosed in JP 4415584B (Patent Document 1). In this film formationmethod, one rotary drum is provided between two rolls, and a pluralityof targets are arranged with respect to the one rotary drum which istransporting a substrate, to enable continuous film formation, therebyincreasing efficiency of the film formation operation.

JP 2010-236076A (Patent Document 2) and JP 07-098854A (Patent Document3) disclose a film formation method capable of subjecting particularlyboth sides of a substrate to film formation, using the roll-to-rolltechnique. In this film formation method, with a view to enablingdouble-side film formation, two rotary drums and one take-up rolldisposed between the rotary drums are used, wherein a substrate fed froma feed roll is subjected to film formation through the two rotary drumswhich are rotating in respective opposite directions, and then rolled upon the take-up roll.

LIST OF PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: JP 4415584B

Patent Document 2: JP 2010-236076A

Patent Document 3: JP 07-098854A

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

A layer structure required for the functional film may vary from deviceto device to which these functional films are applied, and it may alsovary depending on performance required for the functional film. For thisreason, it is desired to develop a film formation method capable ofproducing, for example, a layer structure subjected to vacuum filmformation on its both sides in an efficient and low-cost manner using asimple configuration of apparatus.

However, the techniques disclosed in the documents such as the PatentDocuments 2 and 3 are capable of forming a film on both sides of asubstrate, but do not make it clear in what manner various treatmentssuch as degassing, annealing and film formation are specifically appliedin performing the double-side film formation, and do not have aconfiguration that can flexibly apply these treatments depending on awide variety of laminate structures. For this reason, these techniquesare likely to fail to sufficiently perform heating after completion offilm formation, causing a problem that a material of the formed film isfail to be fully crystallized.

Further, in these conventional apparatuses, a target is fixed at aposition spaced apart by a predetermined distance with respect to arotary drum. Thus, in order to perform maintenance on the target etc.supported by a cathode electrode, it is necessary to stop the filmformation operation. This causes a problem of deterioration inefficiency of the film formation operation etc.

The present invention has been made to solve the above problems in theconventional techniques, and an object thereof is to provide a filmformation method, under the roll-to-roll technique, promoting, inparticular, optimization of double-side vacuum film formation andcapable of producing a laminate subjected to vacuum film formation onits both sides in an efficient and low-cost manner, by appropriatelyapplying treatments such as heating treatment in a suitable positionusing a simple configuration of apparatus.

In addition, it is also an object of the present invention to provide afilm formation method capable of increasing efficiency of a filmformation operation by allowing a cathode electrode requiringmaintenance to be removed from a film formation chamber while continuingthe required film formation operation.

Means for Solving the Problem

In order to accomplish the above object, according to an aspect of thepresent invention, there is provided a method for continuouslysubjecting an elongated substrate to vacuum film formation. The methodcomprises the steps of: a) unrolling and feeding an elongated substratewound in a roll form from a first roll chamber in a direction from thefirst roll chamber toward a second roll chamber, using a first surfaceas a surface for film formation; b) degassing the substrate fed in thedirection; c) forming, in a first film formation chamber, a firstmaterial film on the first surface of the degassed substrate; d)forming, in a second film formation chamber, a second material film onthe first material film formed on the first surface of the substrate; e)taking up, in the second roll chamber, the substrate in a roll form, thesubstrate having the second material film laminated on the firstmaterial film on the first surface of the substrate; f) unrolling andfeeding the substrate taken up in the second roll chamber from the firstroll chamber in the direction, using a second surface opposite the firstsurface as a surface for film formation; g) degassing the substrate fedin the direction; h) forming, in the first film formation chamber, thefirst material film on the second surface of the degassed substrate; i)forming, in the second film formation chamber, the second material filmon the first material film formed on the second surface of thesubstrate; and j) taking up, in the second roll chamber, the substratein a roll form, the substrate having the second material film laminatedon the first material film on each of the first and second surfaces ofthe substrate. According to this aspect of the present invention, alaminate comprising the first material film and the second material filmrespectively laminated in this order on the first surface and the secondsurface of the substrate is obtained in one apparatus. The firstmaterial may be a transparent conducting layer, and the second materialfilm may be a metal such as copper, copper alloy, silver or silveralloy.

In the above method, when taking up the substrate in the second rollchamber, the substrate having the second material film and the firstmaterial film laminated in this order on the first surface of thesubstrate, the substrate may be removed in the second chamber in a statewhere a part of the substrate is communicated with a load lock mechanismprovided between the second roll chamber and an adjacent chamber to thesecond roll chamber while shielding between the second roll chamber andthe adjacent chamber using the load lock mechanism. This makes itpossible to keep all the chambers other than the second roll chamber ina vacuum state during the above operation. In the above method, whenunrolling and feeding the substrate from the first roll chamber in thedirection, using a second surface of the substrate as a surface for filmformation, the second surface of the substrate may be set as a surfacefor film formation in a state where a part of the substrate iscommunicated with a load lock mechanism provided between the first rollchamber and an adjacent chamber to the first roll chamber whileshielding between the first roll chamber and the adjacent chamber usingthe load lock mechanism. This makes it possible to keep all the chambersother than the first roll chamber in a vacuum state during the aboveoperation.

Further, in the above method, the substrate may be subjected to a plasmatreatment in a period after it is fed from the first roll chamber andbefore the first material film is formed thereon. This makes it possibleto strengthen the effect of the plasma treatment.

In the above method, the substrate may be degassed in a heating chamberin a period after it is fed from the first roll chamber and before thefirst material film is formed thereon. Further, the substrate may bedegassed in a heating chamber in a period after it is fed from thesecond roll chamber and before the second material film is formedthereon. The substrate may be degassed in the first film formationchamber when it is being guided in the direction. This makes it possibleto strengthen the effect of the degassing.

In the above method, when forming, in the second film formation chamber,the second material film on the substrate fed in the direction, a firstcathode electrode in the first film formation chamber may be removedfrom the first film formation chamber. According to this aspect of thepresent invention, in the first film formation chamber, maintenance onthe target of a material can be performed, while continuously performinga film formation operation in the second film formation chamber, so thatit becomes possible to increase production efficiency.

In the above method, the substrate having the second material filmformed thereon may be subjected to an annealing treatment. This makes itpossible to strengthen the effect of annealing treatment.

Effect of the Invention

The present invention makes it possible to provide a film formationmethod capable of producing a laminate subjected to vacuum filmformation on its both sides in an efficient and low-cost manner using asimple apparatus configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating one example of a filmformation apparatus capable of implementing a film formation methodaccording to the present invention.

FIG. 2 is a schematic diagram illustrating an example structure of alaminate obtained by the film formation method according to the presentinvention.

FIG. 3 is a schematic diagram illustrating an arrangement of a cathodeelectrode achievable by the film formation method according to thepresent invention.

FIG. 4 is a schematic diagram illustrating another apparatusconfiguration capable of implementing a film formation method accordingto the present invention.

DESCRIPTION OF EMBODIMENTS

With reference to the accompanying drawings, a preferred embodiment ofthe present invention will now be described.

FIG. 1 illustrates one example of a film formation apparatus 1 capableof implementing the present film formation method. For example, the filmformation apparatus 1 comprises: a first roll chamber W1 and a secondroll chamber W2 each capable of housing an elongated substrate 10 woundin a roll form; a first film formation chamber 41 and a second filmformation chamber 42 each provided between the first roll chamber W1 andthe second roll chamber W2; a first heating chamber 31 provided betweenthe first roll chamber W1 and the first film formation chamber 41; asecond heating chamber 32 provided between the second film formationchamber 42 and the second roll chamber W2; and a plasma treatment device40 provided between the first heating chamber 31 and the first filmformation chamber 41. To simply present the apparatus configuration,these elements may be positioned in a nearly linear fashion asillustrated. Further, it is only necessary for this apparatus to includethe elements capable of implementing the present film formation method,but other elements may also be included. This will be further describedbelow.

The film formation apparatus 1 in FIG. 1 is adaptable to any processsuch as a vacuum vapor deposition process, a sputtering process, and achemical vapor deposition (CVD) process. Among them, the sputteringprocess is capable of achieving large-area uniform deposition andforming a dense thin film, with high continuous productivity andexcellent production stability. In the sputtering process, particularly,DC Magnetron Sputtering is capable of forming a magnetic field on asurface of a target to confine electrons near the target so as tosuppress damage to a substrate. These treatments are performed withkeeping each chamber in a vacuum state.

In order to effectively maintain a vacuum state, a partition 14 isprovided between adjacent ones of the chambers of the film formationapparatus 1. Each of the partitions 14 is provided with a slit 13 forallowing the substrate 10 to pass therethrough. Further, in order toeffectively maintain the vacuum state of the chambers other thanoperating space, load lock mechanisms 13, 13′ may be provided. The loadlock mechanism has been well known, and thus the description thereofwill be omitted here.

The substrate 10 to be used in this method may be made of a materialallowing a film to be formed thereon, such as one of a wide variety ofresin films including a PET film, or one of a wide variety of metalfilms including an aluminum sheet, and the material is not particularlylimited. However, the substrate 10 is formed as a member having agenerally elongated shape, and flexibility enough to be wound into aroll form. During film formation, the substrate 10 is fed using an arrayof guide rollers 29 and others, in a roll-to-roll manner, i.e., betweenthe first roll chamber W1 and the second roll chamber W2 etc., in adirection A from the first roll chamber W1 toward the second rollchamber W2.

In order to wind the substrate 10 into a roll form, a first feed/take-uproll 21, and a second feed/take-up roll 22 are provided in the firstroll chamber W1 and the second roll chamber W2, respectively. When thesubstrate 10 is fed in the direction A, the first feed/take-up roll 21performs an unrolling (feed-out) operation, and the second feed/take-uproll 22 performs a rolling-up (take-up) operation.

In the first and second heating chambers 31, 32, the substrate 10 isheated and subjected to treatments such as degassing treatment andannealing treatment. The obtainable effect varies depending on theirinstallation position and a usage mode of the film formation apparatus1. For example, the first heating chamber 31 provided between the firstroll chamber W1 and the first film formation chamber 41 can heat anddegas the substrate 10 before film formation in the first film formationchamber 41. During a vacuum process or the like, water is likely to comeup to a surface from an inside of the substrate 10. In this case, suchwater has a great impact on a composition of a film to be formed. In thefilm formation apparatus 1, the heating chamber 31 provided at the aboveposition may remove water to reduce the negative impact.

In addition, the second heating chamber 32 provided between the secondfilm formation chamber 42 and the second roll chamber W2 makes itpossible to heat the substrate 10 after subjecting the substrate 10 tofilm formation in the second film formation chamber 42, therebyannealing a material of a film formed on the substrate 10 to change theatomic arrangement of the film such that crystal grains are regularlyarranged. Alternatively or additionally, a heating chamber may beprovided, for example, between the first film formation chamber 41 andthe second film formation chamber 42, according to need. However, theheating chamber is not necessarily required. For example, a heatingfunction provided by a rotary drum in the film formation chamber may beutilized to obtain the same effect without providing the heatingchamber.

The plasma treatment device 40 is used to subject the substrate 10 to aplasma treatment. The plasma treatment allows a surface of the substrate10 to be activated and cleaned, thereby allowing the subsequent filmformation to be more effectively performed. As with the heating chamber,an installation position of the plasma treatment device is notparticularly limited. For example, utilization of the plasma treatmentdevice 40 provided between the first heating chamber 31 and the firstfilm formation chamber 41 makes it possible to subject the substrate 10to the plasma treatment before film formation in the first filmformation chamber 41. Alternatively or additionally, a plasma treatmentdevice may be provided, for example, between the first film formationchamber 41 and the second film formation chamber 42, according to need.However, the plasma treatment device is not necessarily required.

It is only necessary to provide at least two film formation chambers.However, an additional film formation chamber may be provided. Aninstallation position of the additional film formation chamber is notparticularly limited as long as it is located between the first rollchamber W1 and the second roll chamber W2. For example, the additionalfilm formation chamber may be provided between the heating chamber 31and the first film formation chamber 41. A material of a film to beformed in each of the film forming chambers is not particularly limited.For example, it may be a metal such as copper, copper alloy, silver orsilver alloy, or a transparent conducting layer. The silver alloy may bea so-called APC (Ag—Pd—Cu) alloy prepared by adding palladium (Pd) andcopper (Cu) to silver (Ag). In this case, silver may be contained in anamount of 90 atomic % as a primary component of the APC alloy.

The first film formation chamber 41 comprises a first rotary drum 51 anda first cathode electrode 61. The first rotary drum 51 is adapted to berotatable to feed the substrate 10 in a selected one of the direction Aand the second direction B, so that the substrate 10 is fed in theselected one of the A and the second direction B via a periphery of thefirst rotary drum 51. The first rotary drum 51 may have a function ofheating the substrate 10. An effect to be obtained by the heatingfunction of the first rotary drum 10 may be considered to be equal tothat of the heating chamber. Therefore, the first rotary drum 51 may beused as a substitute for the heating function of the heating chamber.Conversely, the heating function of the heating chamber may besubstituted for the heating function of the first rotary drum 51.

The first cathode electrode 61 consists of a plurality of electrodeelements provided with respect to the first rotary drum 51. Morespecifically, each of the electrode elements of the first cathodeelectrode 61 is adapted to be movably disposed in opposed relation tothe first rotary drum 51, while supporting a target for forming a filmof a predetermined material. The predetermined material to be formed asa film may be freely selected depending on a usage mode of the filmformation apparatus 1. For example, when the substrate 10 is passedaround the first rotary drum 51 in the direction A, the predeterminedmaterial may be set to a first material. The material may be freelychanged depending on the usage mode of the film formation apparatus 1.During a period of time in which the substrate 10 is passed around thefirst rotary drum 51, a film of the predetermined material will beformed on the substrate 10 using the first cathode electrode 61.

The second film formation chamber 42 has the same or similarconfiguration and functions as/to those of the first film formationchamber 41, and comprises a second rotary drum 52 and a second cathodeelectrode 62. The second rotary drum 52 is adapted to continuously feedthe substrate 10 at least in the direction A via a periphery thereof,while heating the substrate 10. The second cathode electrode 62 consistsof a plurality of electrode elements adapted to be disposed around andin opposed relation to the second rotary drum 52. The material in thesecond cathode electrode 62 may also be freely selected as the firstcathode electrode 61. For example, a predetermined material of a targetto be supported by the second cathode electrode 62 may be set to asecond material when the substrate 10 is passed around the second rotarydrum 52 in the direction. The material film may be freely changeddepending on the usage mode of the film formation apparatus 1. During aperiod of time in which the substrate 10 is passed around the secondrotary drum 52, a film of the predetermined material will be formed onthe substrate 10 using the second cathode electrode 62.

The heating in each of the first and second rotary drums 51, 52 and thefilm formation are mutually independent functions. Thus, for example,the film formation apparatus 1 can be controlled such that the firstfilm formation chamber 41 performs only the heating, and the second filmformation chamber 42 performs only the film formation. With a view toallowing the heating to be sufficiently performed, each of the first andsecond rotary drums 51, 52 may be configured to have a relatively largediameter and thereby increase a feeding time with respect to thesubstrate 10.

With reference also to FIG. 2, one example of this film formation methodusing the film formation apparatus 1 will be described below. In thisfilm formation method, same treatments are repeated at least twice, butthe surface for film formation is reversely set in each of thesetreatments. For convenience, each of these treatments will be referredto as a first treatment and a second treatment. FIGS. 2(a) and (b)respectively illustrate a laminate obtained after completion of thefirst treatment, i.e. an intermediate process, and a laminate obtainedafter completion of the second treatment, i.e. a final process.

In the first treatment, firstly, the substrate 10 is unrolled and fedfrom the first roll chamber W1 in the direction A using one surface a(referred to as “first surface”, for convenience) as a surface for filmformation. The fed substrate 10 is degassed using a heating function ofthe first heating chamber 31 or the first rotary drum 51 of the firstfilm formation chamber 41. Subsequently, a first material film 10-1 isformed on the first surface a of the substrate 10 that has been degassedin the first heating chamber 31 or is being degassed using the firstrotary drum 51 of the first film formation chamber 41, using the firstcathode electrode 61 of the first film formation camber 41, andsubsequently, a second material film 10-2 is formed on the firstmaterial film formed on the first surface a, using the second cathodeelectrode 62 in the second film formation camber 42, and then thesubstrate 10 is once rolled up in the second roll chamber W2. As aresult, a laminate shown in FIG. 2(a), namely a laminate comprising thefirst material film 10-1 and the second material film 10-2 laminated inthis order on the substrate 10 is obtained.

In the subsequent second treatment, the same treatment as the firsttreatment is repeated. However, before starting the treatment, it isrequired to transfer the substrate 10 from the second roll chamber W2 tothe first roll chamber W1 to allow the second surface b opposite thefirst surface a to be used as the surface for film formation. First, thesubstrate 10 is removed from the second roll chamber W2. This operationis performed in a state where a part of the substrate 10 is communicatedwith a load lock mechanism 13′ provided between the second roll chamberW2 and second heating chamber 32 adjacent to the second roll chamber W2,while shielding between the second roll chamber 32 and the secondheating chamber 32 by the load lock mechanism. This makes it possible tomaintain all the chambers other than the second roll chamber W2 in avacuum state during the above operation, and eliminate the need to bringthe entire film formation apparatus 1 again in a vacuum state after theoperation, reducing the hours of operation and enhancing efficiency ofthe film formation operation. Thereafter, the substrate 10 is set in thefirst roll chamber W1 to allow the second surface b to be used as asurface for film formation. As with the removing operation, this settingoperation is also performed in a state where a part of the substrate 10is communicated with a load lock mechanism 13 provided between the firstroll chamber W1 and an adjacent chamber to the first roll chamber, suchas the heating chamber 31 while shielding between the first roll chamberW1 and the first heating chamber 31 by the load lock mechanism 13. Thus,it possible to maintain all the chambers other than the first rollchamber W1 in a vacuum state.

After setting the second surface b as the surface for film formation inthe first roll chamber W1, the substrate 10 is fed from the first rollchamber W1 in the direction A and degassed using a heating function ofthe first heating chamber 31 or the first rotary drum 51 of the firstfilm formation chamber 41. Subsequently, a first material film 10-1 isformed on the second surface b of the degassed substrate 10, using thefirst cathode electrode 61 of the first film formation camber 41, andsubsequently, a second material film 10-2 is formed on the firstmaterial film formed on the first surface a, using the second cathodeelectrode 62 of the second film formation chamber 42, and then thesubstrate 10 is rolled up in the second roll chamber W2.

From the above processes, the laminate shown in FIG. 2(b), namely alaminate comprising the first material film 10-1 and the second materialfilm 10-2 respectively laminated in this order on the first surface aand the second surface b of the substrate 10 is obtained. The first andsecond materials are not particularly limited. For example, the firstmaterial film 10-1 may be made of a transparent conducting layer, suchas ITO, and the second material film 10-2 may be made of a metal, suchas copper (Cu), copper alloy, silver (Ag) or silver alloy (e.g., APCalloy). In the case where the second material film 10-2 is made of ametal, this metallic material would block the heating of the ITOconstituting the second material film 10-2. Therefore, particularly inthis case, it is preferable to provide a heating chamber (not shown)between the first film formation chamber 41 and the second filmformation chamber 42, in other words, to subject the substrate 10 to anannealing treatment in a period after the first material film 10-1 isformed and before the second material film 10-2 is laminated. Properheating of the ITO in these heating chambers makes it possible toappropriately control the crystal condition and provide an amorphous orcrystalline ITO in an optimal condition. In the above embodiment,description has been made based on a method of producing a laminate onboth sides of the substrate 10. However, it is to be understood that thefilm formation treatment may be further repeated on both sides or oneside of the substrate 10.

With Reference to FIG. 3, an arrangement of a cathode electrodeachievable by the present film formation method will now be describedbelow. FIG. 3 is a schematic plan view illustrating an arrangement ofthe first cathode electrode 61 in the first film formation chamber 41and the second cathode electrode 62 in the second film formation chamber42, to be achieved when a film is formed on the substrate 10.

Obviously, when the second material film 10-2 is formed in the secondfilm formation chamber 42, all that is necessary for the first filmformation chamber 41 is that the first rotary drum 51 of the first filmformation chamber 41 can perform heating (degassing), but it is notnecessary to perform film formation using the first cathode electrode61. Thus, the degassing or the like in the first film formation chamber41 may be performed in a state where the first cathode electrode 61 isremoved from the first film formation chamber 41, for example, by movingan electrode body 60 supporting the first cathode electrode 61, asillustrated in FIG. 3. As a result, the first cathode electrode 61removed from the first film formation chamber 41 can be subjected tomaintenance such as replacement, and the film formation in the secondfilm formation chamber 42 can be continuously performed even during themaintenance, so that it becomes possible to increase productionefficiency of the substrate 10. An opening of the first film formationchamber 41 for allowing the first cathode electrode 61 to be removedfrom the first film formation chamber 41 therethrough may be closed by atemporary cover or the like, if necessary.

In this film formation method, in a period after feeding from the firstroll chamber W1 and before formation of the first material film 10-1 inthe first film formation chamber 41, the substrate 10 can be subjectedto a plasma treatment, using, for example, the plasma treatment device40 provided between the heating chamber 31 and the first film formationchamber 41. Further, in a period after the first material film 10-1 isformed and before the second material film 10-2 is formed in the secondfilm formation chamber 42, the substrate 10 can be subjected to a plasmatreatment, using, for example, a plasma treatment device (not shown)provided between the first film formation chamber 41 and the second filmformation chamber 42. Such a plasma treatment makes it possible toeffective perform the subsequent film formation.

In this film formation method, in a period after feeding from the firstroll chamber W1 and before formation of the first material film 10-1 inthe first film formation chamber 41, the substrate 10 can be subjectedto degassing, using, for example, the first heating chamber 31 providedbetween the first roll chamber W1 and the first film formation chamber41. Further, the substrate 10 can be subjected to degassing when it isbeing guided in the direction A, using, for example, a heating functionprovided by the first rotary drum 51 of the first film formation chamber41.

Further, the substrate 10, having the first material film 10-1 and thesecond material film 10-2 formed on the first surface a or on the firstsurface a and the second surface b, can be subjected to an annealingtreatment, using, for example, the second heating chamber 32 providedbetween the second film formation chamber 42 and the second roll chamberW2.

FIG. 4 illustrates another apparatus configuration capable ofimplementing the present film formation method. In FIG. 4, the sameelement or component as in FIG. 1 is designated by the same referencenumeral or code as that in FIG. 1. It is only necessary for the elementor component constituting the film formation apparatus 1 to be arrangedto allow the present film formation method to be implemented. Thus, thefilm formation apparatus 1 does not necessarily employ the configurationof FIG. 1, and for example, it may employ the configuration of FIG. 4.

For example, the film formation apparatus 2 comprises the first rollchamber W1 and the second roll chamber W2 of the film formationapparatus 1 as shown in FIG. 1, as well as a third roll chamber W3, anadditional plasma treatment device 40′ provided between the heatingchamber 31 and the first film formation chamber 41, a load lock 13′provided between the third roll chamber W3 and the second film formationchamber 42, and switching rolls 83, 83′ for changing a route of thesubstrate 10. However, the film formation apparatus 2 has the same basicconfiguration as the film formation apparatus 1, namely, for example, atleast two film formation chambers are provided between each rollchamber, and thus the present film formation method may be implementedalso by such a configuration.

For convenience, a feed path to which switching is performed by theswitching roll 83′ is referred to as “first feed path”, while a feedpath to which switching is performed by the switching roll 83 isreferred to as “second feed path”. As shown in FIG. 1, in a period aftera substrate 10 is unrolled and fed in a first direction A from the firstroll chamber W1 toward the second roll chamber W2 through until itreaches at least the switching roll 83, the substrate 10 moves along thecommon part regardless of the above feed paths. However, after reachingthe switching roll 83, in the first feed path, the substrate 10 isturned around by the switching roll 83′ and thereby fed to pass throughthe second film formation chamber 42 in the second direction B, asindicated by the broken line, whereas, in the second feed path, thesubstrate 10 is fed to pass through the second film formation chamber 42in the first direction A, as indicated by the solid line. Obviously,when the present film formation method is implemented, the second feedpath indicated by solid line is used. The detail of the film formationoperation is as described above.

The above description has been made based on an example where two filmformation chambers are provided. However, it is to be understood that afilm formation apparatus comprising three or more film formationchambers can obtain the same effects. Further, as described inconnection with the configurations of the first and second filmformation apparatuses, a heating chamber or a plasma treatment devicemay be appropriately provided at an adequate position, and the filmformation method of the present invention may be implemented in a filmformation apparatus incorporating it.

The present invention includes these various changes and modificationsencompassed within a technical scope thereof.

INDUSTRIAL APPLICABILITY

The method according to the present invention may widely be used forvarious types of film formation apparatus.

EXPLANATION OF CODES

-   1: film formation apparatus-   10: substrate-   13: load lock-   14: partition-   29: guide roll-   31: heating chamber-   40: plasma treatment device-   41: first film formation chamber-   42: second film formation chamber-   51: first rotary drum-   52: second rotary drum-   60: main body-   61: first cathode electrode-   83: switching roll-   W1: first roll chamber-   W2: second roll chamber-   W3: third roll chamber

What is claimed is:
 1. A method for continuously subjecting an elongatedsubstrate to vacuum film formation, comprising the steps of: a)unrolling and feeding an elongated substrate wound in a roll form from afirst roll chamber in a direction from the first roll chamber toward asecond roll chamber, using a first surface as a surface for filmformation; b) degassing the substrate fed in the direction; c) forming,in a first film formation chamber, a first material film on the firstsurface of the degassed substrate; d) forming, in a second filmformation chamber, a second material film on the first material filmformed on the first surface of the substrate, and removing a firstcathode from the first film chamber while forming, in the second filmformation chamber, the second material film on the substrate fed in thedirection; e) taking up, in the second roll chamber, the substrate in aroll form, the substrate having the second material film laminated onthe first material film on the first surface of the substrate, andtransferring the substrate from the second roll chamber to the firstroll chamber; f) unrolling and feeding the substrate taken up in thesecond roll chamber from the first roll chamber in the direction, usinga second surface opposite the first surface as a surface for filmformation; g) degassing the substrate fed in the direction; h) forming,in the first film formation chamber, the first material film on thesecond surface of the degassed substrate; i) forming, in the second filmformation chamber, the second material film on the first material filmformed on the second surface of the substrate; and j) taking up, in thesecond roll chamber, the substrate in a roll form, the substrate havingthe second material film laminated on the first material film on each ofthe first and second surfaces of the substrate.
 2. The method as definedin claim 1, wherein transferring the substrate from the second rollchamber to the first roll chamber comprises removing the substrate fromthe second roll chamber in a state where a part of the substrate iscommunicated with a load lock mechanism provided between the second rollchamber and an adjacent chamber to the second roll chamber whileshielding between the second roll chamber and the adjacent chamber usingthe load lock mechanism.
 3. The method as defined in claim 1, whereinwhen unrolling and feeding the substrate from the first roll chamber inthe direction using a second surface of the substrate as a surface forfilm formation, the second surface of the substrate is set as a surfacefor film formation in a state where a part of the substrate iscommunicated with a load lock mechanism provided between the first rollchamber and an adjacent chamber to the first roll chamber whileshielding between the first roll chamber and the adjacent chamber usingthe load lock mechanism.
 4. The method as defined in claim 1, whereinthe substrate is subjected to a plasma treatment in a period after it isfed from the first roll chamber and before the first material film isformed thereon.
 5. The method as defined in claim 1, wherein thesubstrate is degassed in a heating chamber in a period after it is fedfrom the first roll chamber and before the first material film is formedthereon.
 6. The method as defined in claim 1, wherein the substrate isdegassed in the first film formation chamber when it is being guided inthe direction.
 7. The method as defined in claim 1, wherein thesubstrate having the second material film formed thereon is subjected toan annealing treatment.
 8. The method as defined in claim 1, wherein thefirst material is a transparent conducting layer and the second materialis a metal.
 9. The method as defined in claim 8, wherein the metal isselected from a group consisting of copper, a copper alloy, silver and asilver alloy.